Despite your fears of not being able to get back, I would first install the update to 5.03. That corrects a number of issues that will benefit you. Second is to have a look whether you have the latest Red drivers/plug-ins. Third would be to upgrade memory to 24 GB, which will give a noticeable boost to performance.
I don't think there are any RED plug-ins for CS5. The files are handled natively now.
> I don't think there are any RED plug-ins for CS5. The files are handled natively now.
There's still a plug-in. We just install it now. (A very large number of features are enabled by plug-ins. They're just software libraries.)
Regarding the update to 5.0.3: Yes, it is strongly recommended.
It is normal for a large number of the importerREDserver processes to be running when you open a project, as each of them is used to process and load a RED clip. They do take a lot of memory. (Some might call it a rude amount of memory.) Installing more RAM would be my first step---after installing the Premiere Pro CS5 (5.0.3) update. 1GB per core is not a lot of memory. I have 24GB in my quadcore (so that's 8 cores with hyperthreading), and I don't have any trouble with R3D footage, which is what I use for my daily tests.